13 comments:

I am not sure I got the point here. What are you trying to prove with this experiment? I don't think there is a stone which you cannot damage with specific treatment and still this does not make it worse than another stone.

Ethiopian opal is hydrophane, Australian isn't. Higher water content always in the Ethiopian due to structure on a nanolevel. Many Australians are frightened by the abundance of very bright fine opal rough form Ethiopia and have tried to discredit it.Sad, as this is what the diamond trade did to opal back in Victoria's reign in the earliest days of Australian opal development.Sadder, it's unnecessary, as they are very different and each has its own best place in the market. Each variety has its own virtues and problems and best uses.Saddest of all, a nice opal got cracked....love, mike

I bought Aussie opals to Canada, and the cold cracked them too, but I've yet to see a warning from any opal sellers about the safe temp range for buyers from places with extreme temps. I doubt it would discourage an opal buyer, I did buy another opal, but the knowledge would be appreciated.

It was obvious. The Ethiopian Opal is full of water like a jelly opal and it's more transparent than the common Aussie Opal that you use in the experiment. A guy did a similar experiment by thrown out both opals. The result: The Australian Opal cracked and the Ethiopian did not. You want more people to buy Aussie opals, then lower your prices and make it affordable for everybody, not for the rich only. Both Opals are beautiful in their own right. It's like comparing apples to oranges.

I'm NOT Australian. I have no connection to AU or any mines. I'm an American who simply loves opal. I cab opal as a serious hobby. I don't sell it regularly. Over 20+ years, I've worked with AU,Mexican, Brazilian, and Ethiopian opal. A lot of Mexican opal is hydrophane, like the majority of Ethiopian, so i have extensive experience with hydrophane. Like it or not, AU has the hardest and most stable opal. When I cab opal, I dopp it to a dowel rod, using a hot wax that will quickly cause 2nd degree burns. I "un" dopp them by putting them in the freezer. While cabbing them, I plunge them into cold water to cool them. They get so hot that the wax will melt during the polishing process. I've had a minimum of 70% of the Ethiopian material crack, no matter how much I baby it. Ethiopian material has the most consistent gem color of any opal. It's gorgeous. But very little of it is stable and it's much softer. Not all Ethiopian opal is hydrophane; some is identical to the AU opal and it's durability and stability match the AU material. However, the vast majority is hydrophane, which can crack by virtue of being submerged in water. I've had Ethiopian cabs crack 6+ months after being finished. I store each of my cabs in small gem containers, which sit in 50 jar cases. My Ethiopians sit along side of the AU,Brz, and Mex. Inevitably, it's the Ethiopian cabs that crack. Yes, I've had a couple of AU or others crack as well, but not nearly as many as the Ethiopian material. Just in case you think I'm associated with AU or its miners, I bought some very expensive AU crystal opal rough many years ago. This 200+ carat parcel was the most beautiful opal I've ever laid eyes on. Every one cracked during the cabbing process. For the past 14 years, the remaining material sat in my rough case. I thought it would be stable, so I tried to cab the rest of the material this past summer. I managed to get one single 1.56 carat cab. The rest is in the chip jar. There is unstable opal in all countries, but the Ethiopian material is the most unstable. I'm going to address the price issue. AU miners sell the opal that they mine. Most hold other jobs, because they don't make enough to live off of mining. Ethiopian miners don't have this luxury. The government controls the mines. Only licensed people can own mines or sell the opal. The licenses are prohibitively expensive. The government has left the responsibilty for health abd safety to the mine owners. Needless to say, corporations and those who are able to afford the licences, have no conscience. Mining is a dirty and dangerous job. The Ethiopian miners are extremely vulnerable and poor. They're prevented from selling the rough by their government. The price for Ethiopian opals will increase dramatically, because the government has made it illegal to sell rough outside of the country; they realize that the real money is in finished jewelery. This is great for the mine owners. The miners are left out and get paid a small stipend. Go to YouTube and check out the typical Ethiopian opal mine. If you feel comfortable with this situation, then by all means, pay less for the Ethiopian material. But, do not blame the AU miners for making money that they've earned. It's unfortunate that the Ethiopian miners don't have the same consideration. They actually work harder since the mine owners won't "squander" their profits on mundane things, like proper mining or safety equipment. Life is cheap in Ethiopia. If you decide to double check my information (and I hope you do), make sure that the info is from a reputable source, like a university, not someone who has a vested interest in the opal.

I'm NOT Australian. I have no connection to AU or any mines. I'm an American who simply loves opal. I cab opal as a serious hobby. I don't sell it regularly. Over 20+ years, I've worked with AU,Mexican, Brazilian, and Ethiopian opal. A lot of Mexican opal is hydrophane, like the majority of Ethiopian, so i have extensive experience with hydrophane. Like it or not, AU has the hardest and most stable opal. When I cab opal, I dopp it to a dowel rod, using a hot wax that will quickly cause 2nd degree burns. I "un" dopp them by putting them in the freezer. While cabbing them, I plunge them into cold water to cool them. They get so hot that the wax will melt during the polishing process. I've had a minimum of 70% of the Ethiopian material crack, no matter how much I baby it. Ethiopian material has the most consistent gem color of any opal. It's gorgeous. But very little of it is stable and it's much softer. Not all Ethiopian opal is hydrophane; some is identical to the AU opal and it's durability and stability match the AU material. However, the vast majority is hydrophane, which can crack by virtue of being submerged in water. I've had Ethiopian cabs crack 6+ months after being finished. I store each of my cabs in small gem containers, which sit in 50 jar cases. My Ethiopians sit along side of the AU,Brz, and Mex. Inevitably, it's the Ethiopian cabs that crack. Yes, I've had a couple of AU or others crack as well, but not nearly as many as the Ethiopian material. Just in case you think I'm associated with AU or its miners, I bought some very expensive AU crystal opal rough many years ago. This 200+ carat parcel was the most beautiful opal I've ever laid eyes on. Every one cracked during the cabbing process. For the past 14 years, the remaining material sat in my rough case. I thought it would be stable, so I tried to cab the rest of the material this past summer. I managed to get one single 1.56 carat cab. The rest is in the chip jar. There is unstable opal in all countries, but the Ethiopian material is the most unstable. I'm going to address the price issue. AU miners sell the opal that they mine. Most hold other jobs, because they don't make enough to live off of mining. Ethiopian miners don't have this luxury. The government controls the mines. Only licensed people can own mines or sell the opal. The licenses are prohibitively expensive. The government has left the responsibilty for health abd safety to the mine owners. Needless to say, corporations and those who are able to afford the licences, have no conscience. Mining is a dirty and dangerous job. The Ethiopian miners are extremely vulnerable and poor. They're prevented from selling the rough by their government. The price for Ethiopian opals will increase dramatically, because the government has made it illegal to sell rough outside of the country; they realize that the real money is in finished jewelery. This is great for the mine owners. The miners are left out and get paid a small stipend. Go to YouTube and check out the typical Ethiopian opal mine. If you feel comfortable with this situation, then by all means, pay less for the Ethiopian material. But, do not blame the AU miners for making money that they've earned. It's unfortunate that the Ethiopian miners don't have the same consideration. They actually work harder since the mine owners won't "squander" their profits on mundane things, like proper mining or safety equipment. Life is cheap in Ethiopia. If you decide to double check my information (and I hope you do), make sure that the info is from a reputable source, like a university, not someone who has a vested interest in the opal.

2 last observations. After reading the comments again, I suspect that most folks are comparing the opals on a site like this one, based in AU and specializing in gem AU opals, with the average Ethiopian found in US jewelry stores, non-opal specialty sites, or Ebay. You can't make this comparison. The opals on sites like this, are the rarest in the world. Black gem opals are the 9th rarest gem in the world. Other than a red diamond, which is the rarest in the world, diamonds don't come close. Black gem opals cost more per carat than a fine diamond. The best gem opals are kept in AU, not sold to suppliers (unless you're Harry Winston). As an American, I can say emphatically, that Americans wouldn't know a true gem opal if it sat up and bit them on the whatsus. It's not their fault. We've only been exposed to the junk found in jewelry stores. Until recently, most of it was lab opal, which wholesales for $1/CT. What little real opal that's available, is the waste cut offs from the worst opals. I have much higher quality in my fish aquarium. The Ethiopian opals seen in stores aren't gem quality; they're mine run. True gem Ethiopian opals cost every bit as much as AU opals. Also, I can't figure out why the GIA AU opals cracked or were damaged in the 4 foot "drop" test. I cab on my front porch which is a good 5 1/2 feet high, and 30 feet long x 10 wide. I've had stones flung from the polishing wheel across the porch, slamming into our brick pillars, I've had it flung across and off of the porch, hitting the concrete walkway. Plus I've dropped polished cabs more times than I can remember. I have a ring containing a gem black that I've hit accidentally against concrete. The only damage I've ever done is a very small, superficial scratch on the ring stone. I could only see it from a specific angle. How in the world anyone could drop one and damage it from four feet high, is honestly beyond me. The only thing I can think of is that it was already damaged and weakened in some fashion.

Surfing has developed over the years from being associated with drugs; unemployment and school dropouts to being accepted as a clean mainstream sport around the world. Surfers can now be seen using surfing exercises and surf training to stay fit, strong and healthy to improve dynamic and athletic endeavors in the surf. This article looks at why surfing exercises are so important to improve surfing performance in this day and age. kitesurfing